A broadband network gateway device (BNG) mainly implements two functions, including a network bearer function, which connects a user device to a BNG device to enable a user to access the Internet, and a control implementation function, which works with an authentication system, a charging system, a customer management system, and a service policy control system to implement authentication, charging, and management functions of user access.
A broadband access server is an access gateway oriented to a broadband network application. It is a bridge connecting a broadband access network to a backbone network and providing basic access means and a broadband access network management function. It is located on an edge of a network, provides a broadband access service, implements convergence and forwarding for multiple types of service, and can meet different users' requirements for a transmission capacity and bandwidth usage, and therefore is a core device for broadband user access.
FIG. 1 is an architecture diagram of BNG user Internet access in the prior art. When a user accesses the Internet by using a BNG, a PPPOE or an IPOE Internet access packet is sent to the BNG shown in FIG. 2. The BNG includes a user management module 210 and forwarding module 220. The forwarding module 220 includes a user table and a forwarding table, and is located on a forwarding plane of the BNG. The user management module 210 is located on a control plane of the BNG and configured to control the forwarding module 220. After receiving an Internet access packet, the BNG directly processes the packet. After the BNG performs authentication and authorization using an AAA server and determines that the user is an authorized user, a user management module of the BNG allocates a corresponding resource to the user, including an IP address and the like, and delivers a corresponding table (including a user table and forwarding table) to a data forwarding plane (forwarding chips such as an NP) of the BNG. After acquiring the IP address, the user can normally implement an Internet access behavior using the IP address.
When a user accesses the Internet by using the BNG, the user management module and a user table forwarding module are located on a same BNG. Therefore, a user can access the Internet by using only one BNG. After the BNG breaks down, the user cannot be automatically connected to the Internet by using another BNG. The number of users who access the Internet on each BNG is limited, and therefore capacity expansion is difficult. Though a two-node cluster hot backup technology can resolve a user Internet access disconnection problem, capacity expansion is difficult and a networking technology is complicated. Therefore, the following problems are found in the prior art.
1. A user capacity cannot be expanded flexibly. That is, a user capacity cannot be expanded according to a requirement without changing a networking architecture.
2. If an Internet access device breaks down, by using the active/active two-node cluster technology, a user can only be migrated to a specified device, but the user cannot be automatically migrated to other Internet access devices.